The present invention relates to basket-type devices for extracting stones such as ureteral stones, calaceal stones and other calculus and the like from the renal or biliary systems.
Various types of stone extraction baskets have been used in the past to extract stones and stone fragments from various biological systems. See for example the devices shown in the following U.S. Patents: Bates U.S. Pat. No. 6,099,534, Okada U.S. Pat. No. 6,093,196, Ouchi U.S. Pat. No. 6,077,274, Bilitz U.S. Pat. No. 6,059,796, Foster U.S. Pat. No. 5,989,266, Bates U.S. Pat. No. 5,957,932, Bates U.S. Pat. No. 5,788,710, Bates U.S. Pat. No. 5,496,330, Dormia U.S. Pat. No. 4,612,931, and Segura U.S. Pat. No. 4,590,938.
A typical stone extraction basket includes a wire basket carried by one end of a wire that is received within the lumen of a sheath. The end of the wire opposite the basket is secured to a handle that is used to slide the sheath over the wire, thereby moving the basket into and out of the lumen of the sheath. When the basket is out of the sheath, it expands to receive a stone. The sheath is then moved toward the basket to reduce the size of the basket openings, and the basket and the enclosed stone are removed from the body.
Recently, ultrasonic, laser, and electro-hydraulic techniques have been used to fragment stones in situ. Typically, the stone fragments are left in the body to be excreted. However, in some cases stone fragments may not be excreted as quickly or as completely as desired. Conventional stone extraction baskets are not optimized for the extraction of shattered stone fragments. Thus, a need presently exists for an improved endoscopic stone extraction device that is easier to use and better suited for the extraction of stone fragments.